The flow behaviour of pigments based on flake-form substrates, such as, for example, mica flakes, is frequently unsatisfactory. In a multiplicity of applications, in particular in the printing and inks sector, this does not result in major problems. In addition, pronounced development of dust occurs in the processing of pearlescent pigments, which requires increased equipment complexity for the elimination of the dusts and for cleaning the machines.
The production of pigment granules using inorganic or organic pigments is known to the person skilled in the art. Colour masterbatches having pigment proportions of 20-50% by weight are used for colouring diverse plastic systems. This is usually a two-step process as far as production of the final granules.
The wetting of plastics, such as, for example, nonpolar thermoplastics based on polyolefins, such as, for example, polyethylene, polypropylene, without pretreatment methods, such as, for example, corona discharge or flame treatment, in subsequent coating with aqueous adhesion promoters often results in poor laminate adhesion to the substrate to be coated. This phenomenon is particularly pronounced in the case of the coating of plastic-based supports with flake-form particles. In general, the mechanical properties of the coated substrates are deficient, which is evident, in particular, in the form of abrasion dust and loss of adhesion of the coloured coating from the support substrate in the form of delamination.
Support particles based on glass often require silanisation in order to ensure durable coatings with a flake-form effect pigment with corresponding adhesion to the surface.